Process of making coated textile materials and the articles produced therefrom



Patented Dec. 11, 1945 PROCESS OF MAKING .COATED TEXTILE MATERIALS ANDTHE ARTICLES DUCED THEREFROM Ralph T. K. Cornwell, Fredericksburg, Va",as-

signor to Sylvania Industrial Corporation,- Fredericksburg, Va., acorporation of Virginia No Drawing. Application October 2, 1943,

Serial No. 504,781

4 Claims. (Cl. 117-73) The present invention relates in general towaterproof textiles. More particularly, it relates to waterprooftextiles of the class of oil cloth,

artificial leather, raincoats and the like, and to a process forproducing the same.

Heretofore, in the manufacture of waterproof textiles, such as oilcloth, artificial leather, raincoats, and the like, it has beencustomary to apply a multiplicity of coatings to a fibrous sheetmaterial, such as fabric, felts and paper. The trade would prefer toavoid the use of such multiple coatings but heretofore this has not beenpossible because (a) the fibrous materials, such as textiles, felts andpapers are extremely porous, and the-first two or three coatingsappliedtend merely to sink into the sheet without forming a filmthereover; (b) such fibrous materials are characterized by having asubstantial nap, the fibres of which tend to protrude through thecoatings-and impart an uneven surface to the product; and due to theporosity, certain pin holes continue to exist even after the applicationof two or more coatings. Accordingly, the trade has found that thesedisadvantages can be overcome only by the application of a multiplicityof coatings, it being common in the trade to apply as many as seven oreight coatings in the manufacture of oil cloth, artificial leather andshoe fabric. It is obvious that the application of such a large numberof coatings which must be separately dried is expensive, time consuming,and necessitates the use of a large amount of labor and equipment.

It is a general object of the present invention to provide a fibrousmaterial with a waterproof and/or moistureproof coating which will tena-'cious1y adhere to the material even during immersion in water for anunlimited length of time. It is another object of the present inventionto provide a coated textile, of which the coating will be non-tacky,flexible and waterproof and strongly adherent.

A further object of the present invention is PRO- the sized textile andthe moistureproof top coating to anchor the top coating to the sizedtextile. In the now preferred embodiment the textile is sized with analkali-soluble water-insoluble cellulose ether, the anchor coating is alacquer containing as the film-forming base a urea-formaldehyde resin,and the top coating .consists of a cellulose derivative, a plasticizer,a wax and a wax blending agent.

The invention accordingly comprises a process having the steps andrelation :of one or more of such steps with respect to each oftheothers, and an article of manufacture possessing the features,properties and the relation of elements which will be exemplified andhereinafter described and the scope of the invention .will be indicatedin the claims.

By the term water resisting is meant the ability of the coating materialto remain adhered to the base sheet during immersion in water for 'anunlimited period of time.

to provide a simple and eflicient method of applyinglsa waterproofcoating to n'brous sheet materia Other objects of the invention will beapparent to those skilled in the art from the following detaileddescription.

According to the present invention, there is provided a 'multi-coatedfibrous sheet material comprising a layer of textile sized with analkalisoluble water-insoluble celluiosic material and having amoistureproof top coating, and a water- 5 The textile material Thesizing composition The sizing composition comprises in general anaqueous alkaline disperslon of a non-fibrous cellulosic colloid, such asthe alkali-soluble waterinsoluble cellulose ethers as a class, such, forexample, as alkyl cellulose ethers, hydroxy-alkyl cellulose ethers, andcarboxy-alkyl cellulose ethers; also, natural or degraded cellulosedissolved in inorganic or organic cellulose solvents, such, for example,as alkaline zincate and alkaline stannate solutions, sodium hydroxide,alkali metal perchlorates, cuprammonia, quaternary ammonium bases, andthe like. Also, there may be used'viscose which is a solution ofcellulose xanthate dissolved in aqueous sodium hydroxide solution. Theuse of the alkali-soluble water-insoluble cellulose ethers is preferredover the other cellulosic' colloids because they give stronger filmsthan the solutions of natural or degraded cellulose and they do notrequire desulfurization as is necessary when viscose is used.

The sizing composition may contain optional ingredients, such, forexample, as pigments, dyeresisting intermediate coating disposed betweenstuffs and mineral fillers, flreprooflng agents.

plasticizers; and the like. The textile material is sized by spraying,padding, backfllling or otherwise coating and/or impregnating thetextile with the composition after which the cellulosic colloid iscoagulated on the textile by tpieating the textile with a coagulant ofthe colloid, such, for example, as an aqueous solution of an acid, anacid salt or an acid gas. When using the cellulose ethers, they may becoagulated additionally by hot water. After the cellulosic colloid iscoagulated on the fabric, it may be washed, soured or dried preferablywhile maintaining the textile at a predetermined width. When penetrationof the textile is not necessary as in making a product coated on onesideonly, the sizing composition is applied by backfllling, using acomposition of high viscosity to retard penetration and to cause afilming-over or window-paning" of. the spaces between the yarns orfibres. and/or after coagulation the sized textile is calendered orpassed between doctor blades to lay the nap fibres into the size.

When a degraded cellulose ether or a degraded cellulose is employed asthe size, the dried sized textile is preferably submitted to acalendering operation or ironing at an elevated temperature. such, forexample, as 50 to 100 C. The application of heat and pressure in thismanner serves two purposes, (a) to smooth the fabric (b) to cause asubstantial flow of the cellulosic colloid. While such degradedcellulosic colloids have been I heretofore considered by those skilledin the art,

as non-thermoplastic materials, nevertheless, it has been found thatthey exhibit a substantial thermoplastic flow when subjected to heat andpressure. This novel characteristic is taken advantage of in the presentinvention tolay' the nap fibres and to smooth the surface of the fabricwhereby one is enabled to produce an impermeable and waterproof materialby the application of only two coatings upon the sized and calenderedtextile. The textile is now ready for ,the

application of the i'ntermediateflor anchor coating.

The anchor coating The film-forming agent used in the anchor coating isa film-forming water-resisting material selected from'the classconsisting of drying tor-oil-rnodifled-alkyd, and soy bean-modifiedalkyd resins; among the thermosetting resins there may be usedphenol-formaldehyde resins, urea-formaldehyde resins,melamine-formaldehyde resins. and the like; and among the syn theticrubbers there maybe used co-polymer of butadiene and styrene, e. g.Buna-S," polymer of ehloroprene, e. g. neoprene, co-polymer ofisobutylene and buta-diene, e. g. butyl rubber, polvmer of ethylenedichloride and sodium tetrasulflde, e. g. Thiokol"; also halo enatednatural rubber and the product of treating rubber with stannic chloridee. g. Pliolite," and the like. However. in the now preferred embodiment,the film-f rming agent in the anchor coating is a thermosetting resin inthe thermoplastic heathardenable state.

Before 5 ing have been discovered, for example, the anchor coating maybe obtained by (a) applying the synthetic resins to the sized textilefrom an aqueous solution containing either the individual compounds suchas urea and formaldehyde, which will condense, upon heating with an acidcatalyst, to form the resin, or containing a water-solu-ble intermediatecondensate of the resinforming compounds, e. g. dimethyiol urea, thecondensate being polymerized on the textile by heating to form awater-resisting non-tacky resin, the top coating being subsequentlyapplied; (b) by applying to the textile, an organic solution comprising.an intermediate condensate of the resinsforming compounds which is tackyand soluble in organic solvents, the polymerization being continued onthe textile until the coating is tack-free and water insoluble, the topcoating then being applied.

The foregoing heat-hardenable resins are added to the coating solutionin the incompletely polymerized heat-hardenable state, which means thatthey are capable of later being furtherpolymerized or hardened to atack-free, substantially insoluble stage while included in the coating,for example, of the magnitude of about 0.0001 of an inch in thickness,by the application of heat and/or a catalyst for a period of not longerthan several minutes and at a temperature not exceeding C. Theheat-hardenable resins are cured to give products which are nontacky andsubstantially insoluble in water or the organic solvents used in the topcoating. At the same time, they do not embrittle the coating but enableit to remain soft and pliable and capable 40 of undergoing shrinkage andswelling as the moisture content of the hydrophilic pellicle changeswith variations in atmospheric humidity.

The hardening agent for the heat-hardenable resin may comprise anymaterial which tends to accelerate the polymerization or hardening ofthe resin, as, for example, by the release of acid upon the applicationof heat. Among the hardening coating composition is preferablyof theplasticizing resin type, for example, aresin of the soft type such aspolymerized unsaturated hydrocarbons, for example, polymerizedisobutylene, which is commonly sold under the trade name Vistanex, orsoft alkyd resins. In addition to the plasticizing resins, or in placethereof, organic plasticizers maybe employed such as dibutyl sebacate,dibutyl phthalate, tricresyl phosphate, cyclohexyl butyl phthalate, andthe like, or mixtures of these plasticizers.

There may be added to the intermediate or anchor coating certainoptional ingredients, in particular a secondary film-forming agent, amoistureprooflng agent, such as a wax blending agent, and slip agent.Slip agentsin the anchor coating are advisable when the pellicle has tobe rewound before application of the top coating thereon.

7 The secondary film-forming base of the anchor The top coating The topcoating comprises, in general, a filmforming moistureproof material, butif the filmforming material is not inherently moistureproof orsufliciently flexible there is added a moistureproofing agent, aplasticizer and, optionally, a

blending agent. The film-forming base of the top coating may comprise(a) film-forming organic-solvent soluble cellulose derivatives as aclass, among which may be mentioned cellulose nitrate, celluloseacetate, ethyl cellulose, benzyl cellulose and the like; or (b)film-forming thermoplastic synthetic resins as a class, such, forexample, as the resin resulting from the reaction of polyhydric phenolswith aliphatic polyhalides, polymers of esters of acrylic acid andmethacrylic acid, polyvinyl resins and the like, in particular acopolymer of vinylidine chloride and vinyl chloride; or (c) drying oilsand drying-oil-modified resins, or a mixture of theseclasses of bases;or (d) natural and synthetic rubber and rubberlike materials, such ashalogenated rubber,-rubber hydrohalides, cyclizedrubber derivatives, andthe like.

In the now preferred embodiment the filmforming agent employed as thetop coating comprises nitrocellulose combined with a plasticizer and amoistureprooflng agent.

In the top coating composition there may be employed a compatibleplasticizer such, for example, as a soft alkyd resin or a non-volatileorganic plasticizer, such, for example, as tricresyl phosphate, dibutylphthalate, cyclohexyl butyl phthalate, dibutvl sebacate, and the like.

The moistureproofing agent may comprise a high-melting wax or a wax-likematerial. A high melting paraiiin wax is preferred for this purpose,that is, a paraflin wax melting between 62 and 65 C. is preferred,although other waxes and wax-like materials may be used, for example,ozokerite, ceresin wax, carnauba wax, and the like.

If desired, a suitable wax-blending agent may be added to the coating.As wax-blending agents, there are used substances which arecharacterized, in general, by a low melting point and a solubility inboth hydrocarbon solvents and hydroxyl-containing solvents and bycompatibility with molten paraflin wax, for example,

ester gum, a blown vegetable oil, wax-free dammar, japan wax, and castoroil phthalates.

The foregoing ingredients are suitably dis- I solved in a solvent or amixture of solvents for all of the materials present. Suitable solventsare mixtures of aromatic hydrocarbons, alcohols and esteqs, such asxylene and butanol, or toluene and butyl acetate.

Generally speaking, the organic solvent or both'the intermediate coatingand the top coating is evaporated at an elevated temperature and when amoistureprootlng wax is present in either of the coatings, thetemperature employed is preferably above the melting point of theparticular wax employed.

There maybe added to the topcoating a suitable slip-inducing agent whichis added in accordance with well-known practices 'to enable one.finished sheet to slide over another when stacked. Suitable 'slipagents-are, for example, any comminuted solid,which is insoluble in theingredients of the anchor coating, such, for example, as starch, talc,zinc oxide, calcium carbonate, and the like.

By way of explanation of the invention and not in limitation thereof,the following specific examples of an anchor coating composition for usein the production of a moistureproof waterproof article of the presentinvention will be given;

Example I.A cotton fabric is first wet with on aqueous solutioncontaining /a% of Tergitol.

After squeezing the wet fabric by means of a water mangle, the wetfabric is coated on both sides with an aqueous alkaline solution of ahydroxy ethyl cellulose ether containing 7% of cellulose ether and 7% ofsodium hydroxide, the solution havinga viscosity of 9 compared to pureglycerine. The cellulose ether is coagulatedon the fabric by passing itinto a aqueous solution of sulfuric acid. It is then washed in water andtreated with a solution of /g% soda ash, washed, and then treated withacetic acid solution to neutralize any residual alkali. Thereafter thefabric is plasticizedwith an aqueous solution containing from 3 to 10%monoethanol-- amine sulfamate. The material is then dried on a tenterframe to a desired width. In the dried product the percent ofplasticizer on the weight of the dry cellulose ether is from to Theintermediate or anchor-coating composition is prepared by mixingtogether the following substances:

Film-forming agent: 1 Parts Urea-formaldehyde butanol ether resin 39Plasticize'r:

Alkyd resin 20 Hardening agent:

Maleic acid 10 This composition is dissolved in a'mixture of toluene,xylene, butyl alcohol and butyl acetate,

and after application to the dried sized textile, the solvent isevaporated at an elevated temperature, for example, from 75 to 98 C.During the evaporation of the solvent, the heat causes a furtherpolymerization or hardening of the thermosetting resin to the insolublestage and causes the coating to become firmly anchored to the textile sothat it will not blister when immersed in water.

The fabric bearing the anchor coating is then coated with a compositioncomprising:

Film-forming agent: Parts Nitrocellulose (5-6 see.) 30

Plasticizers: I

Dibutyl sebacate 13 Alkyd resin (Beckaclte") 25 Moistureproofing agent:

Paraffin wax .(M. P-. 67 C.) 5 Wax blending agents: Esterifled Congo gum5 Rapeseed oil 0.5

From 10-20 parts of this composition are dissolved in-200 parts of amixture of 70 a,v toluene, 15% ethyl acetate and 15% butyl acetate. Thissolution is then applied to the sized textile bear ing the anchorcoating and the solvent is evap= orated at an elevated temperature, forexample, from 75 to9 89 .C., that is, above the melting point of thewax.

Example II.The process of Example I is repeated'using, instead of thecellulose ether solution, a solution formed by dissolving groundwoodpulp in an aqueous alkaline solution of sodium zincate containing anexcess of sodium hydroxide, the solution being effected by cooling themixture-to about 8 C. with cracked ice, stirring and warming. Thesolution thus produced is then applied by back-filling to one side of atextile felt, the cellulose coagulated immediately and the alkalineutralized by means of an acid coagulant, after which the felt iswashed and dried. The dried felt is then calendered whereby the surfaceis rendered smooth and the nap fibres coating consisting of Saran (aco-polymer of 80' parts of vinylidine chloride and 20 parts of vinylchloride) dissolved in-suitable solvents, such, .for example, as a warmmixture of toluene and dioxane or a mixture of dioxane and methyl ethylketone. The product thus produced will be found to be highlymoistureproof and resistant to loosening of the coating when the felt issoaked in water. The product thus serves-admirably as a floor covering,artificial leather and the like. It should be noted that in the secondexample no moistureproof wax is employed either in the anchor coating.or in the top coating because the Saran is itself highly moistureproofand water-resisting.

Since certain changes in carrying out the above process and certainmodifications in the composition which embody the invention may be madewithout departing from its scope, it is intended that all mattercontained in the above description hydrophilic alkali-soluble celluloseether insol-' uble in water; coagulating said cellulose ether to form acoating and thereafter applying pressure to said cellulose-ether-coatedfabric while the coagulated cellulose ether coating is in a wet gelstate to cause the coating to flow and lay the nap;

I applying to said coated fabric an intermediate anchor coatingcomprising a hydrophobic thermosetting synthetic resin in anintermediate stage of polymerization dissolved in an organic solvent,said resin being selected from the-group consisting ofphenol-formaldehyde resins, urea-formal- .dehyde resins andmelamine-formaldehyde resins; said cellulose ether coating preventingpenetration of the fabric by said resin solution; thereafter evaporatingthe organic solvent and continuing polymerization of the resin to give anontacky water-insoluble coating; applying to said intermediate coatinga moisture-proofing composition comprising a film-forming cellulosecompound dissolved in a volatile organic solvent, said cellulosecompound being selected from the group consisting of cellulose ethersand cellulose esters; and evaporating said last-mentioned organicsolvent to form a top coating; said intermediate coating anchoring saidtop coating and the cellulose ether coating anchoring the intermediatecoating to the fabric, whereby the various coatings tenaciously adhereto the fabric without cracking or peeling therefrom.

2. The process recited in claim 1, wherein the top coating comprises aplasticizer and a moisture-proof wax.

4o 3. A flexible, water-proof fabric made in accordance with the processdefined in claim 1.

4. A flexible, water-proof fabric made in accordance with the processdefined in claiml, in which the top coating comprises a plasticizer anda moisture-proof wax.

RALPH T. K. CORNWELL.

